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https://www.readbyqxmd.com/read/28436860/effect-on-high-intensity-fields-of-a-tough-hydrophone-with-hydrothermal-pzt-thick-film-vibrator-and-titanium-front-layer
#1
Nagaya Okada, Shinichi Takeuchi
A novel tough hydrophone was fabricated by depositing hydrothermally synthesized lead zirconate titanate polycrystalline film on the back-side surface of a titanium plate. Our developed tough hydrophone resisted damage in a high-pressure field (15 MPa) at a focal point of a sinusoidal continuous wave driven by a concave high-intensity focused ultrasound (HIFU) transducer with up to 50 W of power input to the sound source. The hydrophone was suitable for the HIFU field, even though the hydrophone has a flat-shape tip of 3...
April 24, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28436255/detection-and-characterization-of-small-infarcts-in-the-caudate-nucleus-on-7-tesla-mri-the-smart-mr-study
#2
Rashid Ghaznawi, Jeroen de Bresser, Yolanda van der Graaf, Maarten Ht Zwartbol, Theo D Witkamp, Mirjam I Geerlings, Jeroen Hendrikse
Small infarcts are among the key imaging features of cerebral small vessel disease (CSVD), but remain largely undetected on conventional MRI. We aimed to evaluate (1) imaging criteria for the detection of small infarcts in the caudate nucleus on 7T MRI, (2) intra- and inter-rater agreement, (3) frequency and (4) detection rate on 7T versus 1.5T MRI. In 90 patients (68 ± 8 years) with a history of vascular disease from the SMART-MR study, we defined 7T imaging criteria for cavitated and non-cavitated small infarcts in the caudate nucleus...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
https://www.readbyqxmd.com/read/28434879/sonoluminescence-and-acoustic-emission-spectra-at-different-stages-of-cavitation-zone-development
#3
N V Dezhkunov, A Francescutto, L Serpe, R Canaparo, G Cravotto
The way in which a cavitation zone develops in a focused pulsed ultrasound field is studied in this work. Sonoluminescence (SL), total hydrophone output and cavitation noise spectra have been recorded across a gradual, smooth increase in applied voltage. It is shown that the cavitation zone passes through a number of stages of evolution, according to increasing ultrasound intensity, decreasing pulse period and increasing ultrasound pulse duration. Sonoluminescence is absent in the first phase and the hydrophone output spectra consists of a main line with two or three harmonics whose intensity is much lower than that of the main (fundamental) line...
April 6, 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28429029/derivatization-and-interlaminar-debonding-of-graphite-iron-nanoparticle-hybrid-interfaces-using-fenton-chemistry
#4
Neha Agarwal, Ruma Bhattacharyya, Narendra K Tripathi, Sanjay Kanojia, Debmalya Roy, Kingsuk Mukhopadhyay, Namburi Eswara Prasad
The interfacial debonding of graphite lattices using iron (Fe) nanoparticles and Fenton's reagent is reported, towards the scalable production of few-layer graphene flakes. Acoustic cavitation via a sonochemical route was adapted to produce iron and iron oxide nanoparticles in the graphite matrix. The oxygenated species were introduced into the graphite lattice using a physical method, and then Fenton chemistry was utilized to generate localized hydroxyl radicals at the Fe nanoparticle-graphite interfaces for zipping and self-exfoliation of the defected graphite lattices...
April 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28427680/numerical-modelling-of-ultrasonic-waves-in-a-bubbly-newtonian-liquid-using-a-high-order-acoustic-cavitation-model
#5
G S Bruno Lebon, I Tzanakis, G Djambazov, K Pericleous, D G Eskin
To address difficulties in treating large volumes of liquid metal with ultrasound, a fundamental study of acoustic cavitation in liquid aluminium, expressed in an experimentally validated numerical model, is presented in this paper. To improve the understanding of the cavitation process, a non-linear acoustic model is validated against reference water pressure measurements from acoustic waves produced by an immersed horn. A high-order method is used to discretize the wave equation in both space and time. These discretized equations are coupled to the Rayleigh-Plesset equation using two different time scales to couple the bubble and flow scales, resulting in a stable, fast, and reasonably accurate method for the prediction of acoustic pressures in cavitating liquids...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427678/application-and-mechanism-of-ultrasonic-static-mixer-in-heavy-oil-viscosity-reduction
#6
Chunwei Shi, Wei Yang, Jianbin Chen, Xiaoping Sun, Wenyi Chen, Huiyong An, Yili Duo, Mingyuan Pei
In the present study, heavy oil viscosity reduction in Daqing oil field was investigated by using an ultrasonic static mixer. The influence of the ultrasonic power on the viscosity reduction rate was investigated and the optimal technological conditions were determined for the ultrasonic treatment. The mechanism for ultrasonic viscosity reduction was analyzed. The flow characteristics of heavy oil in the mixer under the effect of cavitation were investigated using numerical modeling, and energy consumptions were calculated during the ultrasonic treatment and vis-breaking processes...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427670/estimation-of-the-distribution-of-low-intensity-ultrasound-mechanical-index-as-a-parameter-affecting-the-proliferation-of-spermatogonia-stem-cells-in-vitro
#7
Zeinab Hormozi Moghaddam, Manijhe Mokhtari-Dizaji, Mansoureh Movahedin, Mohammad Ehsan Ravari
Considering the use of physical and mechanical stimulation, such as low-intensity ultrasound for proliferation and differentiation of stem cells, it is essential to understand the physical and acoustical mechanisms of acoustic waves in vitro. Mechanical index is used for quantifying acoustic cavitation and the relationship between acoustic pressure and the frequency. In this study, modeling of the mechanical index was applied to provide treatment protocol and to understand the effective physical processes on reproducibility of stem cells...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427649/hydrodynamic-cavitation-in-combination-with-the-ozone-hydrogen-peroxide-and-the-uv-based-advanced-oxidation-processes-for-the-removal-of-natural-organic-matter-from-drinking-water
#8
Matej Čehovin, Alojz Medic, Jens Scheideler, Jörg Mielcke, Achim Ried, Boris Kompare, Andreja Žgajnar Gotvajn
Natural organic matter in drinking water is causing concern especially due to the formation of disinfection by-products (DBPs) by chlorine, as these are proven to have adverse health effects on consumers. In this research, humic acid was used as a source of dissolved organic carbon (DOC) in drinking water (up to 3mgL(-1)). The efficiency of DOC removal was studied by applying O3, H2O2/O3, H2O2/UV and O3/UV advanced oxidation processes (AOPs) alone and combined with hybrid hydrodynamic cavitation (HC), generated by an orifice plate, as this technology recently shows promising potential for the treatment of water, containing recalcitrant organic substances...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427626/manothermosonication-as-a-useful-tool-for-lipid-extraction-from-oleaginous-microorganisms
#9
A Meullemiestre, C Breil, M Abert-Vian, F Chemat
Manothermonication is a recognized and efficient method used for sterilization in food preservation. The synergistic effect of sonication combined with pressure and temperature allows enhancing the cavitation activity. Never employed for extraction, this study is about the transposition of this process as a tool of extraction. In this study, Rhodosporidium toruloides yeast was submitted to extraction by four modes of sonication, with a temperature ranged from 20 to 55°C and a pressure between 1 to 2bars. The lipids extraction yields were compared to the conventional maceration...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427623/degradation-of-reactive-blue-13-using-hydrodynamic-cavitation-effect-of-geometrical-parameters-and-different-oxidizing-additives
#10
Sunil Rajoriya, Swapnil Bargole, Virendra Kumar Saharan
Decolorization of reactive blue 13 (RB13), a sulphonated azo dye, was investigated using hydrodynamic cavitation (HC). The aim of research article is to check the influence of geometrical parameters (total flow area, the ratio of throat perimeter to its cross-sectional area, throat shape and size, etc.) and configuration of the cavitating devices on decolorization of RB13 in aqueous solution. For this purpose, eight cavitating devices i.e. Circular and slit venturi, and six orifice plates having different flow area and perimeter were used in the present work...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427614/production-of-graphene-quantum-dots-by-ultrasound-assisted-exfoliation-in-supercritical-co2-h2o-medium
#11
Hanyang Gao, Chen Xue, Guoxin Hu, Kunxu Zhu
In this research, three kinds of graphene quantum dots (GQDs)-pristine graphene quantum dots (PGQDs), expanded graphene quantum dots (EGQDs) and graphene oxide quantum dots (GOQDs)-were produced from natural graphite, expanded graphite, and oxide graphite respectively in an ultrasound-assisted supercritical CO2 (scCO2)/H2O system. The effects of aqueous solution content ratio, system pressure, and ultrasonic power on the yields of different kinds of GQDs were investigated. According to these experiment results, the combination of the intense knocking force generated from high-pressure acoustic cavitation in a scCO2/H2O system and the superior penetration ability of scCO2 was considered to be the key to the successful exfoliation of such tiny pieces from bulk graphite...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427612/study-of-ultrasonic-cavitation-during-extraction-of-the-peanut-oil-at-varying-frequencies
#12
Lei Zhang, Cunshan Zhou, Bei Wang, Abu El-Gasim A Yagoub, Haile Ma, Xiao Zhang, Mian Wu
The ultrasonic extraction of oils is a typical physical processing technology. The extraction process was monitored from the standpoint of the oil quality and efficiency of oil extraction. In this study, the ultrasonic cavitation fields were measured by polyvinylidene fluoride (PVDF) sensor. Waveform of ultrasonic cavitation fields was gained and analyzed. The extraction yield and oxidation properties were compared. The relationship between the fields and cavitation oxidation was established. Numerical calculation of oscillation cycle was done for the cavitation bubbles...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28427542/recurrent-respiratory-papillomatosis-a-state-of-the-art-review
#13
REVIEW
Helena Ribeiro Fortes, Felipe Mussi von Ranke, Dante Luiz Escuissato, Cesar Augusto Araujo Neto, Gláucia Zanetti, Bruno Hochhegger, Carolina Althoff Souza, Edson Marchiori
Recurrent respiratory papillomatosis (RRP) is a benign disease of the upper aero-digestive tract caused by human papillomavirus (HPV) infection, which affects children and young adults. The aim of this review is to describe the main etiological, epidemiological, clinical, diagnostic, and treatment aspects of RRP. Most infections in children occur at birth, during passage through the birth canals of contaminated mothers. In adults, HPV is transmitted sexually. Papillomas usually appear as exophytic nodules, primarily in the larynx, but occasionally involving the nasopharynx, tracheobronchial tree, and pulmonary parenchyma...
May 2017: Respiratory Medicine
https://www.readbyqxmd.com/read/28425493/characterization-of-different-microbubbles-in-assisting-focused-ultrasound-induced-blood-brain-barrier-opening
#14
Sheng-Kai Wu, Po-Chun Chu, Wen-Yen Chai, Shih-Tsung Kang, Chih-Hung Tsai, Ching-Hsiang Fan, Chih-Kuang Yeh, Hao-Li Liu
Microbubbles (MBs) serve as a critical catalyst to amplify local cavitation in CNS capillary lumen to facilitate focused ultrasound (FUS) to transiently open the blood-brain barrier (BBB). However, limited understanding is available regarding the effect of different microbubbles to induce BBB opening. The aim of this study is to characterize different MBs on their effect in FUS-induced BBB opening. Three MBs, SonoVue, Definity, and USphere, were tested, with 0.4-MHz FUS exposure at 0.62-1.38 of mechanical index (MI) on rats...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28417266/guided-longer-pulses-from-a-diagnostic-ultrasound-and-intraclot-microbubble-enhanced-catheter-directed-thrombolysis-in-vivo
#15
Shunji Gao, Qiong Zhu, Xiaoxiao Dong, Zhong Chen, Zheng Liu, Feng Xie
The mechanism of ultrasound thrombolysis (UT) is generally attributed to cavitation. The insufficiency of microbubbles (MB) to serve as cavitation nuclei in the vessel-obstructing thrombi significantly reduces the effectiveness of UT. Taking advantage of the widely performed catheter-directed therapy (CDT), in a thrombo-embolized rabbit IVC model with a simultaneous catheter directed rt-PA thrombolysis procedure, guided moderate mechanical index longer pulses from a modified diagnostic ultrasound transducer, combined with an intraclot infusion of MB, significantly accelerated the thrombolysis process...
April 17, 2017: Journal of Thrombosis and Thrombolysis
https://www.readbyqxmd.com/read/28417261/neutrophil-infiltration-and-matrix-metalloproteinase-9-in-lacunar-infarction
#16
Wolfgang Walz, Francisco S Cayabyab
We use the modified pial vessel disruption rat model to elucidate the cellular and molecular mechanisms of cavitation as it plays a role in lacunar infarction. Here we discuss the similarities between the genesis of pulmonary cavitation in various animal models and lacunar infarction in the cerebral cortex of rats. Both pathological processes involve the creation of a cavity surrounded by fibroblasts or reactive astrocytes. A crucial step in both, the lung and the cerebral cortex, appears to be the migration of neutrophils across the endothelial barrier into the parenchyma...
April 18, 2017: Neurochemical Research
https://www.readbyqxmd.com/read/28415328/asymmetric-transmission-of-sound-wave-in-cavitating-liquids
#17
Xun Wang, Weizhong Chen, Shengde Liang, Taiyang Zhao, Jinfu Liang
Two modes of the asymmetric sound transmission are observed experimentally in a one-dimensional system composed of coupled two layers of liquids. Their cavitation thresholds are different from each other. When the sound wave propagates from the high-threshold liquid to the low-threshold liquid, the two liquids can avoid the cavitation for a medium driving pressure. When it propagates from the low-threshold liquid to the high-threshold liquid, however, the low-threshold liquid can be cavitated by the same driving pressure, though the high-threshold liquid remains uncavitated...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28415266/cavitation-and-spallation-in-liquid-metal-droplets-produced-by-subpicosecond-pulsed-laser-radiation
#18
M S Krivokorytov, A Yu Vinokhodov, Yu V Sidelnikov, V M Krivtsun, V O Kompanets, A A Lash, K N Koshelev, V V Medvedev
The deformation and fragmentation of liquid metal microdroplets by intense subpicosecond Ti:sapphire laser pulses is experimentally studied with stroboscopic shadow photography. The experiments are performed at a peak intensity of 10^{14}W/cm^{2} at the target's surface, which produces shock waves with pressures in the Mbar range. As a result of such a strong impact, the droplet is transformed into a complex-shaped hollow structure that undergoes asymmetrical expansion and eventually fragments. The hollow structure of the expanding target is explained by the effects of cavitation and spallation that follow the propagation of the laser-induced shock wave...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28413682/multi-focal-hifu-reduces-cavitation-in-mild-hyperthermia
#19
Vandiver Chaplin, Charles F Caskey
BACKGROUND: Mild-hyperthermia therapy (40-45 °C) with high-intensity focused ultrasound (HIFU) is a technique being considered in a number of different treatments such as thermally activated drug delivery, immune-stimulation, and as a chemotherapy adjuvant. Mechanical damage and loss of cell viability associated with HIFU-induced acoustic cavitation may pose a risk during these treatments or may hinder their success. Here we present a method that achieves mild heating and reduces cavitation by using a multi-focused HIFU beam...
2017: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/28413332/fluid-dynamics-of-acoustic-and-hydrodynamic-cavitation-in-hydraulic-power-systems
#20
REVIEW
A Ferrari
Cavitation is the transition from a liquid to a vapour phase, due to a drop in pressure to the level of the vapour tension of the fluid. Two kinds of cavitation have been reviewed here: acoustic cavitation and hydrodynamic cavitation. As acoustic cavitation in engineering systems is related to the propagation of waves through a region subjected to liquid vaporization, the available expressions of the sound speed are discussed. One of the main effects of hydrodynamic cavitation in the nozzles and orifices of hydraulic power systems is a reduction in flow permeability...
March 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
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